The Devil Fighter (Rewrite Version)

After sacrificing his life to protect a friend, Elliot Davidson gets resurrected as a Devil and servant of Rias Gremory. Not only he has to get used his new life while learning that fantastic beings, even mythological Gods, actually exists, but he has to prove to everyone that just because he doesn't have a Sacred Gear or Longinus doesn't make him a worthless Devil. OC x Harem.